Self-loading .[.auger.]. scrapers .Iadd.with a conveyor such as an auger .Iaddend.have complex hydraulic systems with a large number of controls at the operator's cab, and in order to minimize the complexity of the operation it is desirable to combine controls where it is practical to do so. The operator must, of course, be able to move the scraper bowl between an elevated road position and a lower loading and unloading position. There is also a control for the bowl apron which closes the front of the bowl when a load is being transported and which is moved for loading and unloading. The auger must operate during loading, and in the case of a fixed auger must also operate during unloading. There is also a pitch and bounce control which should be operative when the unit is in transport mode but which must be locked out for loading and unloading.
A multiple function scraper control valve includes a control handle for manually shifting the valve to operate the ejector. Under most conditions it is essential that the auger operate when the ejector is operating, because otherwise the ejector will jam material into the auger instead of unloading it through the auger.
In order to minimize the number of controls that the operator must use, it is desirable to provide for operation of the auger when the ejector control handle is moved from a first position to a second position for powering the ejector cylinder.